If you'd been to past iHeartCountry Festivals, you probably arrived at the Erwin Center prepped for the marathon. Free afternoon performances on the venue's north plaza prime the pump for the main event, a 7 p.m. mega-concert that in past years has run till midnight or even beyond.

A modest surprise, then: It was just 11:15 p.m. when headliner Tim McGraw closed his set with "Indian Outlaw," the 1994 hit that was his first top-10 country single. Upon closer examination, this might have been expected. Compared to 2018, when the lineup included 11 acts plus one-song cameos by two special guests, this year's model capped out at nine sets — still a plentiful smorgasbord for the full house of modern country radio fans, but one that left them perhaps a little less drained by the end of the night.

Two acts from 2018 returned this year. Luke Combs, who played both the daytime and evening events last year, set the tone with a strong six-song opening set that included all three of his country radio chart-toppers from the past year: "Beautiful Crazy," "She Got the Best of Me" and "One Number Away." That's the thing about these rapid-fire short sets: Really there's only time to play the biggest hits, and the crowd is just fine with that, happy to sing along gleefully with songs they know by (i)heart.

The other returnee from last year was Dan + Shay, who also played the very first of these events presented by the iHeart Radio conglomerate back in 2014. The Nashville duo hasn't really gotten bigger since that inaugural event, when they were a new face in the lineup, but they've maintained a steady radio presence. They filled their early slot on the bill well, providing a step up from Chris Janson, who had a lot of energy but mostly formulaic songs ("Fix a Drink," anyone?).

The festival, and mainstream country radio in general, has drawn criticism in recent years for being too much of a boys' club, and that remained evident this time around. An attempt to address that was a segment billed as an all-women "guitar pull" that was really just a way to package three female artists into one 25-minute slot rather than giving them their own sets.

And that's too bad, because Lauren Alaina, Tenille Townes and Caylee Hammack all proved worthy of extended time. Alaina, a former "American Idol" runner-up who'd also played the outdoor stage in the afternoon, hit a home run with "Road Less Traveled," the title track to her 2017 album. Canada's Tenille Townes stood out with "Somebody's Daughter," a moving song that digs far deeper than the male artists' tendency toward trucks-and-beers anthems. All three women teamed up for a finale of Shania Twain's 1997 smash "Man! I Feel Like a Woman!", which iHeart would do well to take as a major hint toward rethinking future fest bills. How 'bout a straight-up 5-to-5 male-to-female ratio for the 2020 lineup?

The only other women on the bill were Karen Fairchild and Kimberly Schlapman of Little Big Town, who'd lit up iHeartCountry Fest in the past and did so again tonight. Their 30-minute set at 9:40 p.m. was probably the best overall performance of the night, kicking off with the crowd-pleaser "Pontoon" before proceeding to country chart-toppers "Better Man" and "Girl Crush," the latter a show-stopping ballad that still sounds refreshingly challenging for mainstream radio. A new song called "The Daughters," just released last month, addressed some of the same issues that Tenille Townes's song had touched on previously.

Before Little Big Town, relative newcomers Old Dominion earned their spot on the bill with a well-received five-song set that included "Hotel Key" and "Make It Sweet," both country radio No. 1 hits in 2018. Old Dominion helped to get things back on track after Bobby Bones & the Raging Idiots played a mid-show set that just felt out-of-place. Bones, a former Austin radio personality who's now the toast of the iHeart network in Nashville, is pretty much perfect as the fest's host. But letting his country-comedy band take up a slot that could've gone to another deserving artist felt like a bad step — especially when one of their contributions was nothing more than a rote cover of Bon Jovi's "Livin' on a Prayer."

The home stretch after Little Big Town began with bro-country kingpins Florida Georgia Line mixing old favorites such as "Cruise" with brand new material including "Y'all Boys." They piped in a canned vocal contribution from Bebe Rexha on the 2017 collaborative hit "Meant to Be," but they brought out surprise guest Morgan Wallen to join them for their recent collaboration "Up Down."

McGraw had headlined the fest in 2015, one of those years it stretched past midnight. One of country's biggest stars since the mid-1990s, he's proven to be a fine actor as well (with a quality turn opposite Oscar winner Sandra Bullock in "The Blind Side"). But on this night, it felt like he was trying too hard. The P.A. volume increased noticeably when McGraw took the stage, as if he was trying to stake his spot at the top of the lineup simply by being louder than anyone else. That's antithetical to one of the great joys of this festival: The crowd loves to sing along, but they also want to HEAR themselves singing along, and that was difficult at the decibel level of McGraw's set. A welcome break from the onslaught was a new ballad, "Hallelujahville," from an album reportedly due out later this year.

RELATED— Listen to Austin360 Radio discuss Willie Nelson's recent birthday: